kopia lustrzana https://github.com/Jean-MarcHarvengt/MCUME
69 wiersze
2.5 KiB
Plaintext
69 wiersze
2.5 KiB
Plaintext
|
|
; ============================================================================
|
|
; VGA output - base layer (15 instructions)
|
|
;
|
|
; file derived from the PicoVGA project
|
|
; https://github.com/Panda381/PicoVGA
|
|
; by Miroslav Nemecek
|
|
;
|
|
; ============================================================================
|
|
; Control word of "dark" command (left shift):
|
|
; - bit 0..7 (8 bits) output color (set to 0 if not used)
|
|
; - bit 8..26 (19 bits) loop counter N
|
|
; - bit 27..31 (5 bits) jump address
|
|
; Control word of other commands (left shift):
|
|
; - bit 0..27 (27 bits) loop counter N
|
|
; - bit 27..31 (5 bits) jump address
|
|
; Clocks per pixel: minimum 2, maximum 17.
|
|
|
|
.program vga
|
|
.side_set 1 ; SYNC output (no opt, wait can be max. 15)
|
|
.origin 17 ; must load at offset 17 (BASE_OFF)
|
|
|
|
; ===== [3 instructions] SYNC pulse, N=delay in clock cycles - 3
|
|
|
|
public sync:
|
|
out x,27 side 1 ; [1] get length of SYNC pulse - 3, start of SYNC pulse
|
|
sync_loop:
|
|
jmp x--,sync_loop side 1 ; [N+1] loop
|
|
public entry:
|
|
out pc,5 side 1 ; [1] get next control word and jump to function
|
|
|
|
; ===== [4 instructions] DARK (or color) pulse, N=delay in clock cycles - 4
|
|
; Sets color output at time +1
|
|
|
|
public dark:
|
|
out x,19 side 0 ; [1] get length of delay pulse - 4, start of delay pulse
|
|
out pins,8 side 0 ; [1] dark output (or color)
|
|
dark_loop:
|
|
jmp x--,dark_loop side 0 ; [N+1] loop
|
|
out pc,5 side 0 ; [1] get next control word and jump to function
|
|
|
|
; ===== [4 instructions] layer synchronisation (delay 9 clock cycles)
|
|
; Output first pixel at time +9 after IRQ
|
|
|
|
public irqset:
|
|
irq clear 4 side 0 ; [1] clear IRQ4 flag
|
|
out null,27 side 0 ; [1] destroy command parameter
|
|
irq set 4 side 0 [5] ; [6] set IRQ flag
|
|
.wrap_target
|
|
out pc,5 side 0 ; [1] get next control word and jump to function
|
|
|
|
; ===== [4 instructions] output pixels at CPP clock, N=number of pixels-2 (number of pixels must be multiple of 4)
|
|
; Output first pixel at time +1
|
|
; Missing 2 clock cycles after last pixel
|
|
|
|
public output:
|
|
out x,27 side 0 ; [1] get number of pixels-2
|
|
output_loop:
|
|
public extra1:
|
|
out pins,8 side 0 [0] ; [1+CPP-2] output pixels (set extra wait CPP-2)
|
|
jmp x--,output_loop side 0 ; [1] loop
|
|
public extra2:
|
|
out pins,8 side 0 [0] ; [1+CPP-2] output pixels (set extra wait CPP-2)
|
|
; missing 1 extra clock cycles - add it to front porch
|
|
; wrap jump to instruction out pc,5
|
|
.wrap
|
|
|
|
|